What will the average MPG be? Poll!

[[es vi: eks]]

I can remember them saying that the FT86 was supost to get reasonal Fuel eccommity.
Can also remember it was supost to be claimed to be 40 to 50Mpg... I very doubt it would be that much tho lol

[Allch Chcar]

As one of the few residents of the forum who give at least half a whoop what the MPG will be I am boycotting this poll because it looks like we are guessing EPA scores(which is like shooting hoops blindfolded for shots of water) and many people voted 30MPG combined which is extremely optimistic even for a "detuned" economy version... That is all.

[Exage]

Will have to have more specs on the engine and final production version of the FT to answer half decent.

I would say it'll best the V6 Competitor models (Camaro, Mustang, and Genesis coupe) sub 20mpg city by at the very least 2-3mpg, the final 6th gear will determine highway and that could go above 30mpg.

[old greg]

Originally Posted by Allch Chcar

30MPG combined ... is extremely optimistic

I'm not so sure about that. I can, and very occasionally do, get 22c/28h in my WRX. If you believe the whp to bhp correction factors (0.75 vs 0.85), a rwd version of my car would get 25/32.

Then there's the weight of the FT86, anywhere from 400 to 700lbs lighter than my car. I'd expect a 1 to 3 mpg improvement in the city from that. Let's split the difference and call it 2.

On the highway, the big differences are going to be the coefficient of drag and the Frontal area. It's hard to speculate on the CdA, but it can't be much can't be any worse than a WRX wagon (0.34), and with the low roofline there's at least a 10% reduction in frontal area. So a 10% reduction in aero drag is a fairly conservative estimate, and the lower weight will see similar losses to rolling resistance. That's an extra 3mpg on the highway.

Then there's the engine itself: Direct injection and presumably ~12.5:1 compression ought to be worth a 5% decrease in BSFC. Let's call it 1 mpg across the board.

Add all that up, and I officially predict 28 city and 36 highway (when driven by a saint).

[DRACHENV6]

I think it will get the same MPG as a civic SI, but with slightly better city numbers due to a lower curb weight.

23 city/31 hwy mpg

[iff2mastamatt]

The EPA will probably give it 26 combined, and that's not too bad in my book.

[Zorro]

Originally Posted by old greg

I'm not so sure about that. I can, and very occasionally do, get 22c/28h in my WRX. If you believe the whp to bhp correction factors (0.75 vs 0.85), a rwd version of my car would get 25/32.

Then there's the weight of the FT86, anywhere from 400 to 700lbs lighter than my car. I'd expect a 1 to 3 mpg improvement in the city from that. Let's split the difference and call it 2.

On the highway, the big differences are going to be the coefficient of drag and the Frontal area. It's hard to speculate on the CdA, but it can't be much can't be any worse than a WRX wagon (0.34), and with the low roofline there's at least a 10% reduction in frontal area. So a 10% reduction in aero drag is a fairly conservative estimate, and the lower weight will see similar losses to rolling resistance. That's an extra 3mpg on the highway.

Then there's the engine itself: Direct injection and presumably ~12.5:1 compression ought to be worth a 5% decrease in BSFC. Let's call it 1 mpg across the board.

Add all that up, and I officially predict 28 city and 36 highway (when driven by a saint).

I don't think the math will all work out that easily. I really don't see your estimated 32mpg combined. That's almost like a corolla and our engine is supposed to be a high compression, high revving beast.

My guess is closer to 26 combined. Maybe 28, and that would be awesome.

[blur]

Fuel efficient performance car . . . I love the idea! As long as it doesnt involve hybrids nd sh!t.

BTW, I voted 28, as MPG was one of the things they were working on in the development of the car . . . and its the reason the engine doesn't have 220hp.

[enc0re]

32 mpg almost like a Corolla? The Corolla gets 30 mpg combined. Source.

[Crashoverride]

After I;m done with it...15, I'm going to be looking into a swap or turbo option ASAP. I might even let a shop use me as a test mule for tuning...Revvvvv... POP well I guess I need a new motor....(Evil Grin) STI or better motor just a phone call away... I need my 300-400HP...damn it.

[Ryephile]

Originally Posted by blur

Fuel efficient performance car . . . I love the idea! As long as it doesnt involve hybrids nd sh!t.

Lotus has been doing it for years. Everyone else "went big" as engine efficiencies were going up, so the improvement was nullified by added mass and huge frontal areas. The current MINI Cooper S is also very good for fuel economy with sporting intentions. The C5 Corvette is actually quite good for highway fuel economy [many get 30 MPG hwy with the huge 5.7L V8].

Great fuel economy + performance is out there. I for one hope the FT-86 can achieve a reasonable blend.

[tranzformer]

Originally Posted by Zorro

our engine is supposed to be a high compression, high revving beast.

High compression actually increases fuel economy. Look at new Mazda Sky engines. It is the constant high revving part that will make a thirsty engine. Stay out of the high revs and it should make for a fairly efficient car.

[Zorro]

^I didn't know that. hmm learn something everyday.

As far as staying out of the high rpms, I don't think thats possible for me.

[Allch Chcar]

Originally Posted by tranzformer

High compression actually increases fuel economy. Look at new Mazda Sky engines. It is the constant high revving part that will make a thirsty engine. Stay out of the high revs and it should make for a fairly efficient car.

This discussion would be better served in the engine tech thread.

I will add this. For example only: in tests like the EPA increasing the Engine efficiency is 1%:3% for every bit of improvement. While weight lost and aerodynamics improved is like 3%:1%. From the EPA fuel economy website.

DI doesn't increase efficiency by more than 3-5%, which is a lot. But 3% more efficiency points at the engine would be something like 12% more MPG on the road.

In general too high of compression can be bad for power after a certain point even though it generally means more efficient combustion. Ask the turbo guys and they'll unanimously demand low compression with a stout stock block. Gasoline Direct injection is better than port or throttle body injection but there are still limitations on the power vs fuel efficiency range for pump gasoline. Ethanol(E85) has a wider curve because but the same theory still applies.